What causes erratic idle on BMW 318 n42 engine when engine is warm.

Tiny
TERENCE MC LEAN
  • MEMBER
  • 2002 BMW 318I
  • 108,000 MILES
The vehicle works fine for the first twenty or so minutes then begin to give an erratic idle thereafter. This increases when ac, and head lights are turned on.
Thursday, March 15th, 2012 AT 8:21 PM

1 Reply

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Have the alternator and fuel pressure checked-also refer to this links:https://www.2carpros.com/articles/engine-misfires-or-runs-rough

1.Defective spark plugs

2.Inadequate spark/coil,defective spark plug wire.

3.Lack of compression

4.False air leakage.

5.Faulty fuel injectors.

6.Insufficient fuel pressure.

7.Contaminated fuel.

8.EGR valve that is leaking.

9.Oxygen sensors.

10.Throttle position sensor.

11.Manifold absolute pressure sensor

12.Mass Airflow Sensor

13.Idle air control valve

Note: If it doesn't apply disregard it-
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Friday, March 16th, 2012 AT 12:35 AM

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